Method of and apparatus for burning fuel



J. -B. swoRD METHUU 0F AND APPARATUS Fon BURNING FUEL File'd Marc@ 1 1924 2 Sheets-Sheet 1 y' A TTORNEY.

Oct. 20 l925- .1. B. swoRD METHOD 0F AND APPARATUS FOR BURNING FUEL Fued Maron 1, 1924 2 shuts-sneer -2 u I l] lml. .1 1 .mfmn A N u.. 114.1% 1. N Q MA1 nmuhwnw +1. u 'Nm-N11 Rm... w Nm. MM n 1 Il I 1| N.

La t l ATTORNEY.

Patented Oct. 20, r1925.

UNITED ls *luATEs' PATEISIT OFFICE.'

, JAMES R. SWORD, or PHILADELPHIA, PENNSYLVANIA, AssIGNoRY'Io SWORD a KIM- BER COMPANY, OP PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF DELA- WARE.

. rlxE'rrIoD or AND APPARATUS POR BURNING FUEL.

Application nled March 1, 1924. serial No. 696,119.

-To all whom may concern.'

Be it known th-at I, JAMES B. SWORD, a citizen of the United States, residing in the city and county of-Philadelphia, State of' Pennsylvania, have invented certain new and useful Improvements in Methods of and Apparatus for Burning Fuel, of 4which the following is a specification.

My` invention relates to a method of and apparatus for burning fuel, such as coal, finely divided solid fuel, and more particularly fiuid fuel, such as gas, and particuchamber or preliminary .combustion cham` ber while. in mixture wlth gases -comprising products of combustion and oxygen, the latter present in proportion less than in air or insufficient to maintain and effect high rate of and substantially perfect combustion, the aforesaidl gases being circulated,v as by a blower or equivalent, from Within the -furnace,'fire box flue or chimney to' the interior of the fire pot, mixing chamber or preliminary combustion chamber, the aforesaid preliminary combustion being followed by the principal and substantially complete combustion at higher rate, both stagesl of combustion being accompanied by admission of `air into` the system at such' rate or in Such quantity as finally to*v effect 'complete or substantially complete combustion, wit-hout, particularly in the .calsejwhen the fuel isl oil, deposition ofcarbon or soot, except in inconsequently quantities.

Further in accordance with my invention,

kerosene, gas oil, fuel oil, or any other Suitable oil Or fluid fuel is delivered at suitable rate into a chamber, as a fire pot, mixing chamber or preliminary' combustion. chamber in which it is converted into vapor or gaseous phase, andthe vaporous or gase- -ous fuel is therein mixed with hot gases as Oxygen in mixture with the nitrogen of alrand gaseous products of combustion circulated from a pointor region Within the fire box or furnace external to the fire pot or preliminary combustion chamber to the interior` thereof, causing the aforesaid preliminary or low rate of'combustion followed 1n another region, as at, near or above the upper end of the fire pot, mixing chamber or preliminarycombustion'chamber by substantially Icomplete combustion at higher rate.

Further in accordance with my invention, the circulating gases arepreferably delivered into the fire pot, mixing chamber 4or burner structure, tangentially or .other- Wise suitably to effect a whirling or vortical movement of the mixture of circulating gases and fuel which progresses longitudi- .nally, preferably upwardl through the,

burner structure, mixing'c amber or preliminary combustion chamber, the preliminary or low rate combustion of the fuel taking place during its whirling or vortical movement. f

Fin-ther "in' accordance `with `my invention, the fuel is burned under conditions avoiding roar ornoise. l

My invention resides in the method and apparatus' of the character hereinafter described and claimed. l

This applicationis in parta' continuation of my prior applicationv Serial 'NO. 627,057, filed March 23, 1923.

. For an understanding of my method, and for an illustration of some o'f the various forms my apparatus may take, reference is to be had to the accompanying drawings,

which: 1

lFig. l is a perspective vview of my system, partly in section, andgcomprising in part a diagram of a control circuit.

Fig. 2 is a verticalI sectional yiew, p artly in elevation, taken on the'line 2,-'2' of i Fig. 3, showing themixing chamber or'- presociated fuel-delivering structure.

#.Fig. 3 is a horizontal sectional View, partly in plan, taken on'the line 3-'3 of Fig. 2. Fig. 4 1s a transverse sectional view of oil straining structure.

Fig. 5 is a sectional view, partly 1n elevation, on. the line 5-5 of Fig. 4.

Referring to Figs. l to 3 inclusive,'H represents a wall of a fire box or heater in general, and' more particularly of a fire box or heater having structure, not shown, for transferring the heat to suitable vheating medium, as air, water,vapor or steam, utilized, for example, for heating a dwelling or other building. The re box or chamber F within the wall H is connected as usual to a flue or chimney, not shown. p

Disposed within the fire box or furnace F is the fire pot, mixing chamber, preliminary combustion chamber or burner structure A, of any suitable form or construction, but preferably, Ias indicated, of circular form. The structure A may be cast or molded in a unit or in sections ofany suitable material, as cast iron orother metal, or of nonmetallic material, such as refractory earth materials, as fire clay, or the like.

ln the example illustrated the chamber A l comprisesthe bottom section which may be provided-with the lugs or feet @by which fboxor furnace chamber F. Superimposed upon the section a: is the section d, upon which is superimposed the upper or top sei:- tion e having the inwardly and downwardly curved ledge or flange f, forming the outlet opening g and the interior annular chan` nel h. i. t

Communicating with the interior of the structure A, as by threading into the section d, isthe metallic pipe z', at whose lower side adjacent its outlet is secured the lug or member integral with or carrying the target or impact member, or'v disk c of any suitable shape, as circular, and preferably inclin ed inwardly and upwardly at any suitable 4 L- gle, for example, 45 degrees. The tar'gei c 1s of anyfsuitab'le material which will with'- stand the temperatures involved, and may hegof -nichrome for any suitablerefractory I'netal, or of carborundum, or equivalent.

' 1 Extending throughA the wall of the pipe a' isl a `pipe m, controlled by valve ln., having" the outlet or nozzle o delivering fuelgas or illuminating gas, or equivalent, to effecta" pilot flame which is directed againstv and heats the target If:` or, in general, serves to.

ignite-the `fuel, as in starting the system. Surrounding the pipes m and z' is the tub-e p, of asbestos or other suitable material of poor heat conductivity, the tube p vfitting' in the opening g in the furnace wall H and at its inner end closely approaching, or, as in' dicated, abutting .against the structure A,

notch or opening rrtlirough which fresh or vatmospheric air enters from the exterior'of the furnace Wall H through the tube p and through the notch orl passage 1 into the fire box or furnace F, exterior to the structure A., and preferably in a position such that the incoming air will impinge upon the fire pot A or otherwise be preliminarily heated.

Upon the outer end of the pipe 'i is dis-v posed the fuel-delivery structure D comprising the cap s threaded on the end of the pipe c' and the cylinder t threadedinto the .i

'tending to the left of the reduced portion y is the pin or needle a, of a size adapted to pass through and preferably closely fit the orifice u when the piston structure movesv toward the left from its position indicated in Fig. 2. Communicating with the bore w adjacent its left endisv the pipe al, which delivers oil or other fluid fuel under suit,-v able pressure. Upon the end of the cylinder t is threaded the member b1, whose invS terior communicates with the bore to .and

with .whose interior communicates the pipe e1, which returns any oil escaping past the piston a to the fuel supply tank. Threaded into the end of the fitting b1 is the plug or gland'dl, throughwhich extends the longi i0' the piston a: toward the left, as viewedrin Fig. 2. A

V'on'the rod e1 is the co'l- An electric motorM, receiving current from the supply circuit'conductors h1 and effected withinthe fire box or furnace F,- drives the fuel or oil pump P, whose suc- I tion is connectedby the pipe jl with the fuel tank or reservoir R containing the oil or other liquid fuel supplied from timefio time through the filling pipe t1.

strainer structure S comprising the member n1, to which is secured by screws o1, Figs. Ll and 5, the chambered member p1, with which' l connects the aforesaid oil delivery pipea 130 Between the gasket g1 and the member p1 is 'rhe- I discharge of the "pum-p P connects pipe 731 with the chamber m1 of the oil the hollowe returns oil to the tank R. I

By suitably adjusting valve s2 in pipe s1, the desired degree of oil pressure within the strainer S and in the oil-delivery pipe al may be procured. Connecting with the return pipe s1 through a Y fitting u1 is the oil drain pipe 01, with which/ may connect the aforesaid pi e c1, and which connects with or concave bo-ttom a of the structure A, whereby any oil collecting therein will be returned to the tank R, the stream of oil throughthe pipe s1 eecting a suction at the fitting u1 drawing the oil through the pipe v1 and delivering it into the tank R.

Driven by the motor M, through shaft (ce1, is the rotary element of the gas-forcing or pumping structure B, which preferably takes the form of a blower or fan whose rotary element may be of the turbine, fan or other suitable or equivalent type, which has the effect not only of moving gases, but.`

also of churning them andfcausing their tho-rough intermixturean'd thereby eliminating stratification.

The suction of the blower B is connected by the tube or 'ductyl lwith the interior of the heater 'H, or with vthe flue or chimney, the inlet being disposed preferably near the bottom of the rebox or furnace F or below the top of the structure A; furthermore, as

indicated in Fig. l, it is preferable that the intake ofthe duct y1 be inclined to facilitate withdrawal o f gases from the region below to the top of structure A. The discharge of the blower B is connected by the "duct al with the tangentially directed inlet struc-v ture a2, increase in velocity being effected, if desired, by the constriction or-nozzle zz; Gases are accordingly withdrawn from the furnace vF through the duct y1 and returned through the duct e into th fire pot, mixing chamber, burner or preliminary combustion chamber A and delivered --therein tangen- -tially, whereby 'there is effected withinthe structure A la whirling or vertical movement of the returned gases in mixture with fuel, the target la being placed edgewise with respect to theV whirlinor gases.

The operation is as follows: l

Illuminatingor fuel gas iscontinuously supplie-d through'the pipem, at suitably low.

rate controlled by the valve n, continuously maintaining at the outlet or nozzle 0, avflame which is preferably directed toward or impinges upon the impact member k, keeping it at suitably elevated temperature and serving also to'ignite the fuel, each time delivery of fuel is resumed.

The motor M, which is started when- I ever the'contacts ofthe thermostat T close the circuit, and which stops ,whenever the contacts separate, in response to chauffes in temperature adjacent the thermostat, rives the blower'B and thepump P, which latter effects a continuous forced circulation of oil .from the sto-rage tank R through the chamber m1' of the strainer structure S parallel to one face of the strainer member?41 and returning to the tank R through the pipe s1.-

There is accordingly a continuous stream member r1 and thence through the pipe S1 to the fuel-delivery structure D.

Upon the resumption ofoil pressure in the pipe al, when the motor M starts, oil is delivered into the left end of the large bore fw, into the space surrounding the member y ofsmaller diameter,thereby exerting a pressure on the left end of the piston causing it to move toward the right, in opposition to spring g, and thereby withdraw the pin or needle .2 from the nozzle orifice u, thereby permitting oil under pressure to bey forced through the nozzleorifice u. When the motor M stops, the pressure of the oil in the,

pipe a1 falls,'and the spring g moves the plunger toward the left, causing the needle or pin e to pass through the nozzle orifice 'u and close it. The repeated movements of the needle z through theorifice u keeps it clean, removing therefrom all deposits which might otherwise `accumulate 'in and clog.

,the nozzle orifice. 4

' The oil issues from the nozzle u inthe form of a fine substantially solid stream indicated at b2, Figs. 2 and 3, which impacts upon the impact member 7c, where, due to the impact and the elevated temperature of the target due to its location in the combustion zoneVv and the preliminary heating by the pilot flame, the oil isatomized or .very finely divided and converted into the gaseous or vapor phase. The pressure of the oil as delivered 'to the nozzle u, is sufficiently high, as of the order of fromj20 to 50 [pounds per square inch, to ensure that the oil stream b2 shall have sufficiently high velocity when impacting upon the member k to effect and ensure atomization or"vap or izatlon or equivalent sufficiently fine subdivision of the oil. The fuel is immediately ignited by the pilot flame, and the combustion thereafter continues so long as oil'isA delivered through the nozzle La The oil particles and/or the gas or vapor lintowhich -the oil is. converted, are defiected upwardly by the upwardly inclined target la, into or toward the annular channel z., coming into mixture with the whirling or rotalng gases,

whose movement is effected by the gases circulated through the ducts y1 and .21.v Inasmuch as the oil vapors or gases are heavier. than the hot gases with which they are mixed, they fall .or settle, and in so doing become more and more intimately mixed with the whirling gases.

There accordingly occurs within the fire pot, bu'rner, mixing chamber or preliminary combustion chamber A combustion .of the fuel, the fuel as it burns being whirled or rotated with the hot gases, and the combusopening g the principal combustion takes place at materially higher rate, and this secondary or principal combustion, which is accompanied by blue, or preferably intensely white, flame, iscomplete or substantially so, for little or lno carbon or soot is deposited within the apparatus or within the fire chamber F or upon the surface ofthe heat-ab.- sorbing structure or within the flue or chimrey. The flame itself will produce a slight suction which will cause air drawn in through the tube or duct p to enter into the fire box or furnace F through vthe aperture 1' outsidef'o-f the chamber A, and the oxygen of this fresh air comes into mixturewith'-thev burning fuel and hot gases at and above the outlet opening g, where the higher rate ofl combustion obtains.

The blower B draws hot gases from the fire box F' through the duct y1 and returns them,

still hot, at a temperature ofthe order of 600 to 800 degrees F., through the duct Z1 tangentially into the chamber A, causing the effects described. These gases sfo-circulated by the blower B comprise products of combastion, as,`for example, about 8 per Acent of carbon dioxide, about l per cent ofcarbon monoxide, and about 3 to l() per cent of oxygen. The oxygen content of the circulating gases is less than the oxygen content of fresh air; and the amount of oxygen delivered into the -p'ot' or preliminary combustion chamber A is insufficient to burn all the fuel delivered into the chamber A, the dilution of the oxygen being such as to sustain only -low rate of and imperfect combustion. .In

consequence, within the preliminary combustion chamber A the amountof oxygen present is insufficient to effect completeor substantially complete combustion or high rate of combustion, but the temperatures effected within the chamber A are sufficient to vaporize or gasify the oil impinging upon the target lc, and within the chamber A occurs the retarded or low rate of combustion which may be accompanied to some extent by destructive distillation or cracking of the oil or a part thereof.

However, when )reaching or passing the opening g, the rate of combustion increases because the hotgases and as yet unburned fuel or incompletely burned fuel come into contact with more oxygen as afforded by the air entering through the passage 1', and the combustion rate is increased and the combustion rendered complete or-substantially so, for the gases passing out through the flue or chimney contain oxygen of the order of 2 v or 3 per cent, carbon dioxide of the order of 12 or 14 per cent, and carbon monoxide to the extent of a small fraction of l per cent. It will be understood that all the aforesaid figures are given merely by Way of example, andare descriptive rather than limitive of my invention. The air passage r is preferably located at a point or region remote from the intake end ofthe gas circulating duct y1, so that oxygen shall not be delivered into the chamber A attoo high a rate, and further to prevent stratification of the gases circulated through the duct y1. The blower B, particularly when of the type described, serves by mechanical y action to circulate the gases, and has the further important beneficial effect of thoroughly and intimately churning and mixing the gases and returns the gases Ainto the chamber A without stratification, but in thorough intermixture.

In operation, my combustion system is quiet, without roar or noise, since high pressure atomization .of the oil is not resorted to, nor is there blasting by air, and the movement ofthe gases takes place at velocities sufficiently low to be noiseless, combustion-f supporting air ltaken into the systembeing supplied by the draft causedby either or both in o the combustion at the opening g and the gas circulation effected by the blower B.

In accordance with that yphasev of my invention which relates to -the use of liquid fuel, as oil, the oil is delivered in 'a solid i stream from a. nozzle remote from the 'impact plate or point of atomization, vaporization and initiation of combustion, -and/ there 'is nov atomization or dispersion -of the 011, nor combustion thereof, until 1t reaches the target or .a `point re.-

mote from the oil-delivering nozzle, ,with the result that the collection of .carbon or the like at or upon the nozzle is avoided, but'which would otherwise occur, as in prior systems,.where the combustion is initiated at the point of delivery of .the oil from the nozzle.' Furthermorethe stream .is of cil i D only, without admixture of air, and subdivision and ignition take place only at a substantial distance from the oil discharge.

By utilizing an impact plate or target of/ the character described and positioned edge- Wise to the whirling stream of gases, -there is no sufficient region of low velocity or quietude on the lee side or edge of the target to permit production and 'accumulation of carbon in substantial quantity. A

According to one of the aspects of my invention, there is a circulating stream of gas, containing products of combustion and a reduced amount of oxygen, the stream having a simple motion of translation from the inlet of the duct y1 to the discharge end of theduct el, except for the churning action within 'the blower Band having after discharge from the duct e1 a vortical or whirling movement, during which the fuel islintroduced as such, and not in mixture with air or other combustion-supporting agent, effecting a ,preliminary combustion which is imperfect,

because of small ratio of oxygen to fuel, and whose rate is low. It is a further characteristic feature of my invention that the fresh ,air admitted to the system does not reach the region of low rate of combustion, but comes into the system at a poin't or region beyond the introduction of the fuel and more particularly beyond the region of imperfect and low rate of combustion.

It is a further feature of my invention that the fiame at or adjacent the upper end of the structure A is spread and diffused by creation, as by the described circulation of .the gases of down draft in the furnace or fire box outside of the fire pot or preliminary combustion chamber A.

While I have described my invention more' particularly in its relation to the employment of fluid fuel, as oil or the like, it will be understood that 4my invention in its broader aspects is applicable also to the burning of coal or solid fuel, as in the fire box of a heater or furnace, in which case the stream of gas comprising products of combustion and reduced amount of oxygen may be circulated fromthe fire chamber or furnace back to and through the bed of coals within which bed low'rate of combustion will be effected, followed by higher rate ofcombust-ion as effected by incoming fresh air introduced or becoming effective at a point p or region above or'beyond that at which the prelimina y or low rate of combustion takes place; and in this relation the bed of coals isv in effect the mixing chamber inv which preliminary combustion takes place.

. What I claim is:

l. The method of burning liquid fuel, which comprises atomizing the fuel, effecting mixture thereof with av stream of whirling hot gaseous products of combustion containing oxygen suflicient only partially to burn the fuel, and thereafter effecting sub'- stantially complete combustion in a different region in contact with oxygen of air freshly added ata point beyond the region of mixture.

2. The method of burning liquid fuel, which comprises introducing .atomized fuel as such into a whirling stream of hot gaseous products of combustion containing oxygen and initiating combustion of the fuel while in said whirling stream..v

3. The method of burning liquid fuel` which comprises atomizing the fuel, mixing, the same with a stream of hot gases having oxygen content in lesser proportion `than in air, causing a whirling and longitudinal movement of the mixture to transport vsaid fuel to a region lremote from the region'of first contact between `said fuel and said stream, and there effecting combustionV at vhigher rate by admixture of air.

4. The combination with a furnace, of a m1xing chamber therein, means for dellvering liquid fuel to said mixing chamber,V

atomizlng structure adjacent the point of delivery of said fuel, and means for con' ing system for withdrawing gases from said f furnace and delivering them tangentially into said chamber for inducing a' whirl therein, an impact member, and means for directing a stream of liquid fuel against said member and into said chamber into the whirling vgasestherein, said chamber having a flame opening above the region' of tangential delivery of gases, said circulating sys-4 tem drawing gases from said furnace at a region external to said chamber and adj'a# cent said opening. v

7. The combination with a furnace,.of a mixing chamber disposed therein, a circulating system for withdrawing gases from said chamber and delivering them tangentially into saidy chamber for inducing a whirl therein, an impact member, means for directing a stream of liquid fuel 'against said impact member and into said chamber into the whirling gases therein, and means for delivering alr into said furnace external to dependently of the intake of said circulating system.

8. The combination with a mixing chamber, 'of means for delivering hot gaseous` products of combustion into said chamber tangentially for inducing a Whirl therein, an impact member, and means delivering a jet of liquid fuel against said impact member, whereby said fuel is minutely subdivided and introduced into the whirling gas.

9. In the art of burning liquid fuel, the method which comprises atomizing the fuel, effecting contact of the vatomized fuel with a whirling stream of hot gaseous products of combustion at a temperature suiiciently high to effect substantially complete vaporization of the fuel, and burning the vapormethod which comprises effecting circula-- tion of gaseous products of combustion, causdetermined region in its circuit to partake of whirling movement, and effecting miX- ture and substantially complete Vaporization of the fuel in the still whirling gaseous stream.

l1. The method of burning liquid fuel,

which comprises introducing atomized fuel as such into a whirling stream of hot gaseous products of combustion containing oxygen, and effecting substantially complete vaporization of the atomized fuel While in said whirling stream.

12. The method of burning liquid fuel,

which comprises introducing atomized vfuel as such into a whirling stream ofv hot gaseous products of combustion containing oxygen, and effecting at leastpartial combus-l tion of the fuel while in said whirling stream.

-JAMES B. SWORD. 

